To enable for easier design and assembly of robotic work tools some models may be arranged with only three fixation points for attaching the body to the chassis of a robotic work tool. One assembly is with one fixation point in the front and two in the rear. However, this may cause the body to roll or become tilted during operation or by a slight misalignment when mounting.
Such roll or tilt may affect the lift and/or collision detection of the robotic work tool, which in turn may compromise the operational safety of the robotic work tool.
A solution could be to make the centrally located fixation point wider, thus giving more support. But, a wider fixation point would consume space and it would make the design of the robotic work tool more challenging.
Another solution would be to have one fixation point in each corner of the robotic work tool, however this would be counterproductive as the aim is to reduce the number of fixation points.
A third solution would be to simply tighten the fixation points harder. This would be the first solution that would come to mind—if something moves—tighten it. However, this has several disadvantages including that the body needs to have some degree of movement as otherwise the lift/collision detection may not work, and a too hard tightened fixation point may induce stress to the body which may lead to the body becoming damaged upon impact.
Although the description herein will be given to a robotic work tool having three fixation points it should be noted that the same problem lies with robotic work tools having two fixation points, where both are centrally located. Also, the same problem lies when a fixation point is located far from a side of the body of the robotic work tool. Far here meaning that the weight of the portion of the body extending from the fixation point becoming sufficient enough to influence the rigidity of the body and thereby affect the movement of the body. Designs where this may occur include the designs mentioned above and also a design where a fixation point at one end of the body is arranged at a corner of the body.
There is thus a need for a robotic work tool system that is able to operate with only three fixation points, or with centrally located fixation points.